We were standing in the pouring rain at Sabang Port, waiting for our turn to board a bangka (a traditional Filipino boat) that would take us to the entrance of the Puerto Princesa Underground River, which runs beneath a cave in Palawan, an island province on the western part of the Philippines. At last our bangka arrived, a trimaran with bamboo outriggers either side of its main hull.
The trimaran is a common sight on Philippine waters. The country pioneered this design in its early warships, then adopted it for its…